1) Field of the Invention
This invention relates generally to fabrication of semiconductor devices and more particularly to a method for an deuterium containing anneal for a semiconductor device.
2) Description of the Prior Art
Dangling bonds at the silicon/silicon oxide interface in semiconductor devices are believed to be the cause of observed non-ideal capacitance-voltage characteristics and reduced channel conductance. Low temperature post-metallization annealing in a hydrogen-containing atmosphere is typically used in the semiconductor device fabrication process, to passivate these dangling bonds. During operation, however, transistor performance can degrade, and this degradation has been correlated to the removal of hydrogen from the silicon/silicon oxide interface, due to collisions between heated carriers and the interface. This degradation in hot carrier lifetime (also referred to as HCl lifetime) is exacerbated by the ever ongoing miniaturization of semiconductor devices, and has become a significant limitation in the further shrinkage of semiconductor devices.
A widely used method for minimizing the degradation of HCl lifetime has been to reduce the peak of the electric field in the transistor by appropriate selection of spacer dimensions, and the implantation of ions to form lightly doped regions between the channel and the corresponding source/drain regions of the transistor. Continued miniaturization is severely limiting the usefulness of these techniques.
Another method is to replace hydrogen with deuterium during annealing, taking advantage of the increased strength of the deuterium-silicon bond as compared with the hydrogen-silicon bond.
The importance of overcoming the various deficiencies noted above is evidenced by the extensive technological development directed to the subject, as documented by the relevant patent and technical literature. The closest and apparently more relevant technical developments in the patent literature can be gleaned by considering the following patents.
U.S. Pat. No. 6,436,799: Process for annealing semiconductors and/or integrated circuits—Semiconductor structure manufacturing method for semiconductor device, involves exposing portion of substrate through contact hole and annealing structure in deuterium containing atmosphere—Inventor: Ramkumar, Krishnaswamy; San
U.S. Pat. No. 6,888,204: Semiconductor devices, and methods for same—Passivating semiconductor devices especially silicon MOSFETs—comprises treatment with deuterium so that device resilience to hot carrier effects is increased—Inventor: Lyding, Joseph W.; et al.
US20020031920A1: Deuterium treatment of semiconductor devices—CMOS transistor treatment involves annealing using deuterium whose partial pressure is higher than atmospheric pressure to form more concentration of deuterium at interface between semiconductor and insulating layer regions—Inventor: Lyding, Joseph W.;
U.S. Pat. No. 5,872,387: DEUTERIUM-TREATED SEMICONDUCTOR DEVICES—Passivating semiconductor devices especially silicon MOSFETs—comprises treatment with deuterium so that device resilience to hot carrier effects is increased—INVENTOR: LYDING, JOSEPH W.; CHAMPAIGN
US20030181005A1: Semiconductor device and a method of manufacturing the same—Manufacture of semiconductor device involves forming over n-type and p-type field effect transistors, insulating films for generating tensile stress and compressive in stress channel formation region of the transistors—Inventor: Hachimine, Kiyota; Mitaka, Japan
U.S. Pat. No. 6,573,172: Methods for improving carrier mobility of PMOS and NMOS devices—Fabrication of semiconductor device by forming P-channel and N-channel metal oxide semiconductor transistors in wafer, forming tensile film on P-channel transistor and forming compressive film on N-channel transistor—Inventor: En, et al.
US20040235236A1: Integrated circuit with improved channel stress properties and a method for making it—Integrated circuit comprises silicate glass layer formed only on p-type metal oxide semiconductor transistor or n-type metal oxide semiconductor transistor and etch stop layer formed on silicate glass layer—INVENTOR: HOFFMANN, THOMAS.